[PATCH 5.10 083/717] ASoC: qcom: common: Fix refcounting in qcom_snd_parse_of()

Greg Kroah-Hartman
2020-12-28T14:05:11Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 4e59dd249cd513a211e2ecce2cb31f4e29a5ce5b ]

There are two issues in this function.

1) We can't drop the refrences on "cpu", "codec" and "platform" before
we take the reference. This doesn't cause a problem on the first
iteration because those pointers start as NULL so the of_node_put()
is a no-op. But on the subsequent iterations, it will lead to a use
after free.

2) If the devm_kzalloc() allocation failed then the code returned
directly instead of cleaning up.

Fixes: c1e6414cdc37 ("ASoC: qcom: common: Fix refcount imbalance on error")
Fixes: 1e36ea360ab9 ("ASoC: qcom: common: use modern dai_link style")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201105125154.GA176426@mwanda
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/soc/qcom/common.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/sound/soc/qcom/common.c b/sound/soc/qcom/common.c
index 54660f126d09e..09af007007007 100644
--- a/sound/soc/qcom/common.c
+++ b/sound/soc/qcom/common.c
@@ -58,7 +58,7 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
dlc = devm_kzalloc(dev, 2 * sizeof(*dlc), GFP_KERNEL);
if (!dlc) {
ret = -ENOMEM;
- goto err;
+ goto err_put_np;
}

link->cpus = &dlc[0];
@@ -70,7 +70,7 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
ret = of_property_read_string(np, "link-name", &link->name);
if (ret) {
dev_err(card->dev, "error getting codec dai_link name\n");
- goto err;
+ goto err_put_np;
}

cpu = of_get_child_by_name(np, "cpu");
@@ -130,8 +130,10 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
} else {
/* DPCM frontend */
dlc = devm_kzalloc(dev, sizeof(*dlc), GFP_KERNEL);
- if (!dlc)
- return -ENOMEM;
+ if (!dlc) {
+ ret = -ENOMEM;
+ goto err;
+ }

link->codecs = dlc;
link->num_codecs = 1;
@@ -158,10 +160,11 @@ int qcom_snd_parse_of(struct snd_soc_card *card)

return 0;
err:
- of_node_put(np);
of_node_put(cpu);
of_node_put(codec);
of_node_put(platform);
+err_put_np:
+ of_node_put(np);
return ret;
}
EXPORT_SYMBOL(qcom_snd_parse_of);
--
2.27.0